-
Precambrian
- A. FIRST LIFE APPEARED at 3.5 by
- 1. Simple , single caelled bacteria and algae
- B. LATE PRECAMBRIAN
- 1. Earliest multicelled organisms
-
Paleozoic Era
- A. CAMBRIAN PERIOD
- 1. Earliest organisms with shell
- 2. Earliest fish
- B.LATE ORDOVICIAN PERIOD
- 1. Ealiest land plants
- C.LATE DEVONIAN PERIOD
- 1. Earliest amphibians
- D. PENNSYLVANIA PERIOD
- 1. Earliest reptiles-laid shelled eggs
- E. END OF PALEOZOIC ERA
- 1. Largest mass extinction in earth history
- 2. -90% of all marine species extinct
-
MESOZOIC ERA
- A. LATE TRIASSIC PERIOD
- 1. Earliest true mammals
- 2. Earliest dinosaurs
- B.LATE JURASSIC PERIOD
- 1. Earliest birds
- C.END OF MESOZOIC ERA
- 1. Mass extinctions
-
Cenozoic Era
A. AGE OF MAMMALS
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